___ ___ is the technique of obfuscating or coding data, ensuring that only the person
who is meant to see the information–and has the key to break the code–can read it.
Cryptography
Origins of cryptography
- Ancient Egypt
- Caesar Cipher
- Enigma Machine
Keeping data secret from unauthorized parties
Confidentiality
Ensuring data has not been tampered with
Integrity
Verifying the identity of users and systems
Authentication
ONE Key - encrypts and decrypts
Symmetric Encryption
Public keya nd private key
Asymmetric encryption
one way function- cannot be reversed
cryptographic hashing
SYMM VS ASYMM
Number of keys
SYMM 1
shared key
ASYMM
2 keys public and priv
SYMM VS ASYMM
Speed
SYMM
Very fast
ASYMM
Slow
SYMM VS ASYMM
Key size
SYMM 1
125-256
ASYMM
2048-4096
SYMM VS ASYMM
Key Distribution
SYMM 1
Difficult - must share secretly
ASYMM
Easy - public key is open
SYMM VS ASYMM
Best For
SYMM 1
Bulk data, storage, VPN
ASYMM
Key exchange, signatures
SYMM VS ASYMM
Examples
SYMM 1
AES, ChaCHa20
ASYMM
RSA, ECC, Diffle-Hellman
order in hybrid approach
Handshake»_space; Session Key»_space; Bulk Transfer»_space; Done
(EXAMPLE OF HYBRID HTTPS)
__ is the framework of policies, procedures, and technologies that manage digital certificates and
public-key encryption
Public Key Infrastructure
A trusted organization that issues and signs digital certificates. Acts as the ‘trusted third party’ that vouches for identities
Certificate AUthority
An electronic document binding a public key to an identity. Contains name, public key, validity dates, and CA signature
Digital Certificate
Certificates form a chain of trust from Root CA → Intermediate CA → End Entity. Each level signs the one below it.
Certificate Chain
Gold standard cipher. Used for bulk data, classified communications, and
TOP SECRET material
AES-256
Asymmetric algorithms for secure key establishment and digital
signatures in classified systems
RSA / ECC
Hash function used for data integrity and as part of digital signature
schemes
Secure Hash Algorithm
__ key agreement for establishing shared secrets over
untrusted networks
Diffle-hellman
The technique of obfuscating or coding data, ensuring that only the
intended recipient — who has the key — can read the information.
Cryptography
